Pressure ulcers, also called bed sores, are a major health issue. Bedridden patients, wheelchair bound patients, people with limited mobility or reduced sensation of touch, e.g. those suffering from diabetic peripheral neuropathy, have high risk of developing pressure ulcers (PUs). PUs can develop quickly and are painful for the patient. They are generally resistant to known medical therapy and, are often very difficult to heal. PUs can cause reduced anatomical or functional integrity in patients and can, occasionally lead to life threatening complications. Care for patients suffering from PUs is often time consuming, personnel intensive and expensive. Once developed, PUs increased hospital stay, imposing enormous burden on the healthcare system and diverting precious personnel resources that may be allocated for other patients.
Either static or long-term dynamic or punctual load, which allows pressure marks on an insensitive or passive area on the body, can lead to pressure ulcers if not taken care of in time. Such occurrences of pressure can occlude blood supply to parts of the body leading to tissue ischemia. If such pressure is not relieved over a long period of time tissue ischemia can lead to permanent cell damage causing pressure ulcers. The person with normal sensation and mobility would be immediately alerted while the person without sensation—without knowing it—allows repeated high pressure and/or static load on the same small place on the body. This can create sores or precursors thereof.
For example, patients suffering from diabetic peripheral neuropathy have reduced sensation in their extremities and may not sense a wound or skin damage to their hands and/or feet. In such patients, a wound or skin damage on the foot can occur without detection, and the condition can lead to complications such as severe infection, slow healing wounds and risk of amputation. Therefore it becomes important for staff at the hospital or nursing home to constantly monitor vulnerable areas of the body and especially observe pressure related alteration of the skin that may be precursors of pressure ulcer.
So far, the most effective care for an at-risk patient is to relieve the pressure which, in hospitals, is commonly done by periodically repositioning bed-bound patients. Because every patient has levels of risk of occurrence of PUs depending on factors such as age, sex, disease conditions, blood pressure, nutrition, etc., some patients may need more frequent repositioning than others. Determining the schedule for repositioning is difficult may yet be unable to prevent occurrence of PUs.
Devices for monitoring patients to prevent and/or detect PUs generally include an array of pressure sensors placed in close proximity to parts of a patient's body that are at a higher risk of forming PUs. The pressure sensors record pressure on the at-risk parts and provide the data to a caregiver so that the caregiver may relive the excess pressure from particular parts by suitably repositioning the patient. However, in generally, such devices are expensive and do not, by themselves, absorb or relieve pressure. For example, it would be rather expensive to change a sock having an array of pressure sensors on a daily basis. Furthermore, there may be problems with machine washing and/or autoclaving, as the connection (e.g., a cable) from the sensor to the electronics may not be adequately protected. Moreover, such devices technologies fail to utilize pressure relieving and shock absorbing areas of the patient's body that could otherwise be used. Furthermore, the dimensions of sensor array devices and spatial constraints for placing these arrays in proximity to a certain body part limit the available locations for placement of such devices. For example, while it may be suitable to use such devices on a mattress or a sheet, it may not work in a shoe or a sock because of the limited space available for placing the sensor without chaffing the user's foot.